The purpose of this project is to modify and extend Information Analysis Corporation's MEDLOG clinical data management system into the areas of clinical care and patient management. The specific features to be developed are: 1) Optimal display of text, tabulations and graphics; 2) Comparative summaries to assist in treatment actions; 3) Data inference techniques to handle missing data; 4) Combined reporting and data entry methods; 5) A portable networked system for clinical use; 6) A new type of multi-valued variable; 7) A facility for form letters, reminders, etc.; 8) New types of missing values. The new resulting system will make MEDLOG more appealing to clinicians, thereby encouraging their participation in medical research. It may also improve patient care by providing better data on which to base medical decisions. This project will be conducted with the assistance of the ARAMIS arthritis center at Stanford University. #